Q&A - PSLE Math

[MathIzzzFun]

lee tong fong:

Thanks for your great help MathIzzzFun and skyed. I have 2 more questions need you to solve if possible use model.. Thanks in advance.


1) Jane and Iris had 255 sweet together. Jane had 15 more sweets than Iris. Jane gave away 25% as many sweet as Iris. She was left with twice as many as sweets as Iris.

(a)How many sweets did Iris give away?
(b)How many sweets did Jane have in the end?

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cheers.

[MathIzzzFun]

lee tong fong:

Thanks for your great help MathIzzzFun and skyed. I have 2 more questions need you to solve if possible use model.. Thanks in advance.


2) Sushila went shopping. She spent $588 on 2 dresses, 3 shirts and 2 pairs of
sunglasses. The total amount spent on the dresses was 0.4 of the total amount
spent on the skirts= shirts ? and sunglasses.The total amount spent o the sunglasses was
1/ 3 of the total amount spent on dresses and shirts.

(a)\tHow much did she spend on the 2 pairs of sunglasses?
(b)What was the cost of the third shirt if the average cost of the two shirts was
$88?

Money spent-
dresses : shirts + sunglasses = 2 : 5
dresses : total (dresses + shirts + sunglasses) = 2 : 7

sunglasses : dresses + shirts = 1 : 3
sunglasses : total = 1 : 4

Total amount spent is the same in both cases,
dresses : total --> 8u : 28u
sunglasses : total --> 7u : 28u
shirts --> 28u - 8u - 7u = 13u

28u --> $588, 1u --> $21


a) amount spent on sunglasses --> 7 x $21 = $147
b) amount spent on shirts --> 13 x $21 = $273
cost of 3rd shirt = $273 - 2 x $88 = $97

cheers.

[lee tong fong]

Thanks MathIzzzFun for your detail working solution.


There an typo error for Jane’s sweet and it should be 255-15/2 instead of 255+15/2 =135

[MathIzzzFun]

lee tong fong:

Thanks MathIzzzFun for your detail working solution.


There an typo error for Jane’s sweet and it should be 255-15/2 instead of 255+15/2 =135

It's correct... you may want draw the model = Jane's block (longer) and Iris's block... to find Jane's sweets --> fill in the \"gap\" ie add 15 to get 2 x Jane's blocks...
so Jane's sweets --> (255 + 15) /2 = 135
and Iris's sweets --> (255 - 15)/2 = 120

cheers.

[lee tong fong]

Thanks MathIzzzFun for your contribution. I have 3 more questions that need your help in model or using simultaneous equation .


1)Leon bought some terrapins and guppies for a total of $96. He bought 3 times as many guppies than terrapins. He paid $30 more for the terrapins than for the guppies. Each terrapin cost $10.40 more than each guppy.
a)\tHow many terrapins did he buy?
b)\tWhat was the cost of each guppy?


2)Sally, Yiling and Ali shared a bag of beads. Sally received 3/4of the bag of beads and ¾ of the bead. Yiling received ¾ of the remaining bags of beads and ¾ of the bead. Ali received the last bead in the bag.
How many beads did Sally receive?

3) In the sack of 42 shirts and shorts, 40% of the shirts and 50% of the shorts were soiled. If 24 shirts and shorts were clean, how many soiled shirts and were there?

Thanks in advance

[MathIzzzFun]

lee tong fong:

Thanks MathIzzzFun for your contribution. I have 3 more questions that need your help in model or using simultaneous equation .


1)Leon bought some terrapins and guppies for a total of $96. He bought 3 times as many guppies than terrapins. He paid $30 more for the terrapins than for the guppies. Each terrapin cost $10.40 more than each guppy.
a)\tHow many terrapins did he buy?
b)\tWhat was the cost of each guppy?


2)Sally, Yiling and Ali shared a bag of beads. Sally received 3/4of the bag of beads and ¾ of the bead. Yiling received ¾ of the remaining bags of beads and ¾ of the bead. Ali received the last bead in the bag.
How many beads did Sally receive?

3) In the sack of 42 shirts and shorts, 40% of the shirts and 50% of the shorts were soiled. If 24 shirts and shorts were clean, how many soiled shirts and were there?

Thanks in advance

these have been discussed you may want to do a search with keywords to retrieve the previous posts...

1) http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=755281&hilit=guppies#p755281

2) http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=712005&hilit=Sally%2C+Yiling#p712005

3) T --> shirts, S --> shorts

total :
T T T T T } 42
........S S }

soiled :
T T } 42-24 =18
.. S }

clean:
T T T} 24
.....S}

T --> 24 - 18 = 6
S --> 18 - 2x6 = 6

soiled shirts --> 2 x 6 = 12

cheers.

[SAHMwith2boys]

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

[CoffeeCat]

SAHMwith2boys:

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

I think it means...
For every desk that exists in this fictional mathematical world, there is 4 stools surrounding it.
So there are 4 times as many stools as desks.


Just in case ....
so if number of desks is 1 unit, number of stools is 4 units.
Difference, 3 units = x
Total number of desks & stools = 5x/3

[SAHMwith2boys]

CoffeeCat:

SAHMwith2boys:

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

I think it means...
For every desk that exists in this fictional mathematical world, there is 4 stools surrounding it.
So there are 4 times as many stools as desks.


Just in case ....
so if number of desks is 1 unit, number of stools is 4 units.
Difference, 3 units = x
Total number of desks & stools = 5x/3

Answer provided was:

No. of desks : No. of stools = 1 : 4 = x : 4x
There are x desks.
There are 4x stools.

Anyone can help to decipher why the solution is this and what does the question wants?? :?

[Udon]

happyheart:

MathIzzzFun:

[quote=\"happyheart\"]Hi,

Need help to solve these using model please.

Q) Four children, Wilson, Felicia,Darren and Annabel sat for Math test and scored a total of 318 marks. Wilson and Darren scored the highest and the lowest respectively with a difference of 27 marks. The difference between Felicia's and Darren's score was 5 marks and the difference between Wilson's and Annabel's score was 13 marks. Find their individual scores.

Thank you!

You may want to draw the model ... I will represent Darren's block as 1 unit

Darren --> 1 unit
Wilson --> 1 unit + 27
Felicia --> 1 unit + 5
Annabel --> 1 unit + 14 (*= Wilson's score - 13)

So, 4 units (or 4 blocks in model) + 46 = 318
1 unit --> 68
...with this, the individual can then be worked out...

cheers.

MathIzzzfun...you make both questions look so simple. Thank you![/quote]
Hi Happyheart...

You are now preparing for 2013 PSLE?